LOW-CARBON SECONDARY HARDENING MARTENSITE CLASS STEELS GEAR WHEELS WORKING METHOD Russian patent published in 1995 - IPC

FIELD: metallurgy. SUBSTANCE: gear wheels of low-carbon secondary hardening martensite class steels are subjected to 2 or 3-fold cyclical volumetric hardening under temperature of 900 975 C and holding for 1 3 hours with tempering preceding each hardening and exercised under temperature of 600 675 C for 1 5 hours, tempering, working and nitriding for given depth, that is exercised in two steps: first under temperature of 500 540 C for 10 20 hours, second step under temperature of 450 570 C for 20 40 hours. EFFECT: method improves process of low-carbon second hardening martensite class steels gear wheels working. 1 tbl